1. Field of the Invention
The present invention relates to a roaming mobile communication terminal, an IC card provided in the mobile communication terminal, a mobile communication system, a program executed by the mobile communication terminal, and a communication charge notification method of notifying a user of communication charge information for roaming communication of the mobile communication terminal.
2. Description of Related Art
A mobile communication system includes a home location register (HLR) which manages movement and calling of a mobile communication terminal such as a mobile phone. Information for specifying each mobile communication terminal which receives a communication service in the mobile communication network (home network), location information indicating the location of each mobile communication terminal, subscriber information indicating the basic communication service (e.g. normal telephone call service) provided to each mobile communication terminal, and the like are registered in the HLR. Location registration (attachment) occurs when a mobile communication terminal is turned on or a mobile communication terminal is located in the service area of a home network or a roaming network. The HLR may update location information during attachment. The location information includes a country identification code, a communication network code, and a location code indicating the location of the mobile communication terminal. When the location information differs from the location information at the latest attachment, or whenever the location information is changed due to movement of the mobile communication terminal beyond the service area of the network, the HLR receives a request (location registration request) from the mobile communication terminal through a base station, and the request is registered (location registration). A mobile communication system controls call connection based on the subscriber information registered in the HLR when the mobile communication terminal has made a call or the mobile communication terminal has received a call.
A roaming service such as an international roaming service which allows a mobile communication terminal used in Japan to be used in foreign countries has been realized by a mobile communication system. The term “roaming” means that the communication provider which manages a home network makes an agreement with a communication provider which manages another mobile communication network to provide the home network user with a similar service on another mobile communication network, or means this service.
When the mobile communication terminal issues a location registration request in an area in which the mobile communication terminal can roam (roaming area), the location registration request is transferred to the mobile communication system of the home network through a switchboard to which the mobile communication terminal is connected, whereby the location information stored in the HLR is updated and the location is registered. The HLR transmits the subscriber information to the switchboard to which the mobile communication terminal is connected, and the switchboard controls call connection based on the subscriber information. When the mobile communication terminal makes a call or receives a call in the roaming area, the HLR transmits the subscriber information to the switchboard to which the mobile communication terminal is connected, and the switchboard controls call connection based on the subscriber information.
Various inventions have been made to improve roaming service and increase processing efficiency.
For example, a communication system has been disclosed which provides an appropriate service when distributing content using a roaming service taking the destination country and region into consideration (see JP-A-2004-236182).
A mobile communication service control method and a mobile communication service control system capable of easily providing a service to a roaming user in a roaming area have also been disclosed (see JP-A-2003-61132).